a film of dirt and fingerprints collects on the watch and bracelet robbing them of their luster. Deposits of dirt and grime accumulate between the bracelet links causing corrosion while acting as an abrasive, grinding the metal away.

Over time, the synthetic oils "congeal" or "break down". The tiny gears inside a watch are under tremendous strain - friction is their greatest enemy. Just like a car, a watch needs fresh oil periodically.